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  <div class="section" id="slice-objects">
<span id="id1"></span><h1>Slice Objects<a class="headerlink" href="#slice-objects" title="永久链接至标题">¶</a></h1>
<dl class="var">
<dt id="c.PySlice_Type">
<a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a> <code class="descname">PySlice_Type</code><a class="headerlink" href="#c.PySlice_Type" title="永久链接至目标">¶</a></dt>
<dd><p>The type object for slice objects.  This is the same as <a class="reference internal" href="../library/functions.html#slice" title="slice"><code class="xref py py-class docutils literal notranslate"><span class="pre">slice</span></code></a> in the
Python layer.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySlice_Check">
int <code class="descname">PySlice_Check</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*ob</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySlice_Check" title="永久链接至目标">¶</a></dt>
<dd><p>Return true if <em>ob</em> is a slice object; <em>ob</em> must not be <em>NULL</em>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySlice_New">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PySlice_New</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*start</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*stop</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*step</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySlice_New" title="永久链接至目标">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Return a new slice object with the given values.  The <em>start</em>, <em>stop</em>, and
<em>step</em> parameters are used as the values of the slice object attributes of
the same names.  Any of the values may be <em>NULL</em>, in which case the
<code class="docutils literal notranslate"><span class="pre">None</span></code> will be used for the corresponding attribute.  Return <em>NULL</em> if
the new object could not be allocated.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySlice_GetIndices">
int <code class="descname">PySlice_GetIndices</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*slice</em>, Py_ssize_t<em>&nbsp;length</em>, Py_ssize_t<em>&nbsp;*start</em>, Py_ssize_t<em>&nbsp;*stop</em>, Py_ssize_t<em>&nbsp;*step</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySlice_GetIndices" title="永久链接至目标">¶</a></dt>
<dd><p>Retrieve the start, stop and step indices from the slice object <em>slice</em>,
assuming a sequence of length <em>length</em>. Treats indices greater than
<em>length</em> as errors.</p>
<p>Returns <code class="docutils literal notranslate"><span class="pre">0</span></code> on success and <code class="docutils literal notranslate"><span class="pre">-1</span></code> on error with no exception set (unless one of
the indices was not <a class="reference internal" href="../library/constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> and failed to be converted to an integer,
in which case <code class="docutils literal notranslate"><span class="pre">-1</span></code> is returned with an exception set).</p>
<p>You probably do not want to use this function.</p>
<div class="versionchanged">
<p><span class="versionmodified">在 3.2 版更改: </span>The parameter type for the <em>slice</em> parameter was <code class="docutils literal notranslate"><span class="pre">PySliceObject*</span></code>
before.</p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.PySlice_GetIndicesEx">
int <code class="descname">PySlice_GetIndicesEx</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*slice</em>, Py_ssize_t<em>&nbsp;length</em>, Py_ssize_t<em>&nbsp;*start</em>, Py_ssize_t<em>&nbsp;*stop</em>, Py_ssize_t<em>&nbsp;*step</em>, Py_ssize_t<em>&nbsp;*slicelength</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySlice_GetIndicesEx" title="永久链接至目标">¶</a></dt>
<dd><p>Usable replacement for <a class="reference internal" href="#c.PySlice_GetIndices" title="PySlice_GetIndices"><code class="xref c c-func docutils literal notranslate"><span class="pre">PySlice_GetIndices()</span></code></a>.  Retrieve the start,
stop, and step indices from the slice object <em>slice</em> assuming a sequence of
length <em>length</em>, and store the length of the slice in <em>slicelength</em>.  Out
of bounds indices are clipped in a manner consistent with the handling of
normal slices.</p>
<p>Returns <code class="docutils literal notranslate"><span class="pre">0</span></code> on success and <code class="docutils literal notranslate"><span class="pre">-1</span></code> on error with exception set.</p>
<div class="admonition note">
<p class="first admonition-title">注解</p>
<p>This function is considered not safe for resizable sequences.
Its invocation should be replaced by a combination of
<a class="reference internal" href="#c.PySlice_Unpack" title="PySlice_Unpack"><code class="xref c c-func docutils literal notranslate"><span class="pre">PySlice_Unpack()</span></code></a> and <a class="reference internal" href="#c.PySlice_AdjustIndices" title="PySlice_AdjustIndices"><code class="xref c c-func docutils literal notranslate"><span class="pre">PySlice_AdjustIndices()</span></code></a> where</p>
<div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="p">(</span><span class="n">PySlice_GetIndicesEx</span><span class="p">(</span><span class="n">slice</span><span class="p">,</span> <span class="n">length</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">start</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">stop</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">step</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">slicelength</span><span class="p">)</span> <span class="o">&lt;</span> <span class="mi">0</span><span class="p">)</span> <span class="p">{</span>
    <span class="c1">// return error</span>
<span class="p">}</span>
</pre></div>
</div>
<p>is replaced by</p>
<div class="last highlight-c notranslate"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="p">(</span><span class="n">PySlice_Unpack</span><span class="p">(</span><span class="n">slice</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">start</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">stop</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">step</span><span class="p">)</span> <span class="o">&lt;</span> <span class="mi">0</span><span class="p">)</span> <span class="p">{</span>
    <span class="c1">// return error</span>
<span class="p">}</span>
<span class="n">slicelength</span> <span class="o">=</span> <span class="n">PySlice_AdjustIndices</span><span class="p">(</span><span class="n">length</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">start</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">stop</span><span class="p">,</span> <span class="n">step</span><span class="p">);</span>
</pre></div>
</div>
</div>
<div class="versionchanged">
<p><span class="versionmodified">在 3.2 版更改: </span>The parameter type for the <em>slice</em> parameter was <code class="docutils literal notranslate"><span class="pre">PySliceObject*</span></code>
before.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified">在 3.6.1 版更改: </span>If <code class="docutils literal notranslate"><span class="pre">Py_LIMITED_API</span></code> is not set or set to the value between <code class="docutils literal notranslate"><span class="pre">0x03050400</span></code>
and <code class="docutils literal notranslate"><span class="pre">0x03060000</span></code> (not including) or <code class="docutils literal notranslate"><span class="pre">0x03060100</span></code> or higher
<code class="xref c c-func docutils literal notranslate"><span class="pre">PySlice_GetIndicesEx()</span></code> is implemented as a macro using
<code class="xref c c-func docutils literal notranslate"><span class="pre">PySlice_Unpack()</span></code> and <code class="xref c c-func docutils literal notranslate"><span class="pre">PySlice_AdjustIndices()</span></code>.
Arguments <em>start</em>, <em>stop</em> and <em>step</em> are evaluated more than once.</p>
</div>
<div class="deprecated">
<p><span class="versionmodified">3.6.1 版后已移除: </span>If <code class="docutils literal notranslate"><span class="pre">Py_LIMITED_API</span></code> is set to the value less than <code class="docutils literal notranslate"><span class="pre">0x03050400</span></code> or
between <code class="docutils literal notranslate"><span class="pre">0x03060000</span></code> and <code class="docutils literal notranslate"><span class="pre">0x03060100</span></code> (not including)
<code class="xref c c-func docutils literal notranslate"><span class="pre">PySlice_GetIndicesEx()</span></code> is a deprecated function.</p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.PySlice_Unpack">
int <code class="descname">PySlice_Unpack</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*slice</em>, Py_ssize_t<em>&nbsp;*start</em>, Py_ssize_t<em>&nbsp;*stop</em>, Py_ssize_t<em>&nbsp;*step</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySlice_Unpack" title="永久链接至目标">¶</a></dt>
<dd><p>Extract the start, stop and step data members from a slice object as
C integers.  Silently reduce values larger than <code class="docutils literal notranslate"><span class="pre">PY_SSIZE_T_MAX</span></code> to
<code class="docutils literal notranslate"><span class="pre">PY_SSIZE_T_MAX</span></code>, silently boost the start and stop values less than
<code class="docutils literal notranslate"><span class="pre">PY_SSIZE_T_MIN</span></code> to <code class="docutils literal notranslate"><span class="pre">PY_SSIZE_T_MIN</span></code>, and silently boost the step
values less than <code class="docutils literal notranslate"><span class="pre">-PY_SSIZE_T_MAX</span></code> to <code class="docutils literal notranslate"><span class="pre">-PY_SSIZE_T_MAX</span></code>.</p>
<p>Return <code class="docutils literal notranslate"><span class="pre">-1</span></code> on error, <code class="docutils literal notranslate"><span class="pre">0</span></code> on success.</p>
<div class="versionadded">
<p><span class="versionmodified">3.6.1 新版功能.</span></p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.PySlice_AdjustIndices">
Py_ssize_t <code class="descname">PySlice_AdjustIndices</code><span class="sig-paren">(</span>Py_ssize_t<em>&nbsp;length</em>, Py_ssize_t<em>&nbsp;*start</em>, Py_ssize_t<em>&nbsp;*stop</em>, Py_ssize_t<em>&nbsp;step</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySlice_AdjustIndices" title="永久链接至目标">¶</a></dt>
<dd><p>Adjust start/end slice indices assuming a sequence of the specified length.
Out of bounds indices are clipped in a manner consistent with the handling
of normal slices.</p>
<p>Return the length of the slice.  Always successful.  Doesn't call Python
code.</p>
<div class="versionadded">
<p><span class="versionmodified">3.6.1 新版功能.</span></p>
</div>
</dd></dl>

</div>
<div class="section" id="ellipsis-object">
<h1>Ellipsis Object<a class="headerlink" href="#ellipsis-object" title="永久链接至标题">¶</a></h1>
<dl class="var">
<dt id="c.Py_Ellipsis">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a> *<code class="descname">Py_Ellipsis</code><a class="headerlink" href="#c.Py_Ellipsis" title="永久链接至目标">¶</a></dt>
<dd><p>The Python <code class="docutils literal notranslate"><span class="pre">Ellipsis</span></code> object.  This object has no methods.  It needs to be
treated just like any other object with respect to reference counts.  Like
<a class="reference internal" href="none.html#c.Py_None" title="Py_None"><code class="xref c c-data docutils literal notranslate"><span class="pre">Py_None</span></code></a> it is a singleton object.</p>
</dd></dl>

</div>


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